if you want to submit to stock libraries do you really have to shoot in RAW? I see from reviews that you can get more detail using RAW but is the point more that you can adjust contrast/saturation etc easily afterwards? would best quality JPEGs do detail wise?

I look at RAW as more "forgiving" than JPEG. This means that if for example the exposure was a bit off, then you are much more likely to correct it later if it's RAW. Also, you don't have to worry about whitebalance. I usually shoot RAW+JPEG, and when I go through my potos afterwards, and if some of the JPEG's looks like good pictures, but they seem a bit to hard to rescue in photoshop, then I edit the RAW file(s). after I'm done, I delete all the RAW files to save space. Hope this helps

Something I think a lot of people may not fully understand with the difference in raw vs jpg is that the jpg image is converted in the camera from the raw data. Where the real image difference lies is that raw data is just the accumulated voltage data the sensor received from exposure. Jpg's are rendered in the camera based on presets (some cameras allow you to manipulate these settings) from the camera applied to the raw data. Once the jpg is created the raw data is deleted, saving space. This means that filters, colour corrections, sharpening and compression is added to the jpg by your camera before it is saved. Basically this alters your original data into a more portable, but not necessarily better, format. Raw is admittedly a space hog, but when it is imported into your image editor it is unchanged. This give a better colour space, more image editing options, and the ability to alter white balance or exposure without damaging the data. It is a better option where resources allow.

I like to think of RAW pictures like a Rubiks Cube. You can manipulate how it looks almost endlessly, but there will always be the same number of each color of squares.

If you have a very high hit-percentage of "perfect" (or "submittable" shots) right out of the camera with only very little/few adjustments to make, then JPEG should be enough.

If you on the other hand end up with many shots that are "submittable" with some solid post processing, RAW gives you more freedom and options.

An analogy would be if you were a music-editor: you would always want to edit the non-compressed version of the music instead of the MP3 version, for example. This will allow to do more tweaking without clipping and overamping - you can push your editing a little further. Same thing with RAW - you can push your edits a little further before it looks "clipped".

thanks folks, I've heard a lot about RAW is really just about 'post-production' opportunities, but the reviews on this site show a JPEG and RAW image for each camera and the RAW always seems sharper - therefore isnt image quality alone a reason to shoot in RAW?

The JPGs are processed in camera (sharpening added, contrast adjustments, saturation etc) where as a RAW file is the original data as recorded.

The benefit of RAW is that you can work on PP with the original data and in a lossless environment, the JPG that comes out of a camera has already been compressed once so has lost a certain amount of information, the more you work on and save the JPG file the more information you are losing. All the work you do on the RAW file can be saved without degradation to the image and in most cases can be returned to default settings even after saving, this is obviously not as easy with a JPG and will definitely cause further degradation.

I have heard the argument that things like white balance can be sorted out on a jpg in PS, and whilst this is true I personally feel that each time you use photofilters to alter the whitebalance a little bit of detail is lost, it's pretty much the same as putting a new layer over the top of an image with a given colour and reducing opacity to around 25% each time you do that some of the contrast is lost in the image. Obviously you can also achieve this with colour balance adjustments but that's all time and effort that I would rather not spend on PP when a quick 2sec tweak to a RAW file can do the exact same thing.

The last thing I will add to this is that in that link you showed the JPG on the left has lost a lot of detail, look at the contrast and details in the trees, and the buildings theres a massive difference and not in the favour of the JPG

Mmmm, that's quite a significant difference. I hadn't come across such a difference between a JPG and an "as shot" RAW before. I wonder what exactly is coming into play there.

Even if you forget this visible difference to the two "as shot" versions, the editing or correcting capabilities of the RAW format is second to none. What I really love is the seemingly very wide dynamic range - when you fire up Lightroom and adjust the exposure, for example, you expect there to be very apparent limits to that kind of adjustment (ie clipping, which would occur in flat images like JPG), but it just keeps showing nice gradiations throughout the tonal range! It's the best!

To get back to your original query though; As far as I can see it, there's no reason why you must shoot in RAW for ultra high quality output such as stock, but it can certainly help. As has been stated, it simply allows for much greater flexibility after the shutter has been pressed.
With that said, if you get exposure and white balance right, I don't see why you can't produce a top notch result with a high quality JPEG.. ?

Buuuuut.. When I get my D300, I think I'll shoot in RAW+JPEG no matter what. It just means more hard disks, and a damn good archival regime.

As for editing JPGs - yes it can get very messy if you write and re-write edits over a JPG, but that's what PSDs are for aren't they? Even for the most minute edit I make to a photo, I always save it as a PSD and leave the original as is.. often with layers in the PSD to keep track of and retain my changes. That's for manual editing, or pre-lightroom workflow though. It's irrelevant for tonal adjustments for example, that can be done in Lightroom.

do most slr have jpeg + raw? i was considering getting a nikon d90 and i was wondering if it had it? is their any disadvantage of saving both over one besides storage issues? like does it take longer then jpegs?